Electrical protector.



No. 783,315. PATENTED FEB. 21. 1905.

C. A. ROLFE,

ELECTRICAL PROTECTOR.

APPLICATION FILED APE.21, 1900.

LEiEi lIIVE LIL- :2 EHARIEiA.EU1FE UNITED STATEs Patented February 21,1905.,

PATENT Orrlcri...

CHARLES A. ROLFE, OF CHICAGO, ILLINOIS, ASSIGNOR. BY MESNE ASSIGN-MENTS, TO ROLFE ELECTRIC CO.,

PORATION OF NEIV YORK.

OF ROCHESTER, NEW YORK, A COR- ELECTRICAL PROTECTOR,

SPECIFICATION forming part of Letters Patent No. 783,315, dated February21, 1905.

Application filed April 21, 1900. $erial No. 13,705.

To all whom it may concern:

Be it known that I, CHARLES A. Home, a citizen of the United States,residing at Chicage, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Electrical Protectors,of which the following is a full, clear, concise, and exact description,reference being had to the accompanying drawings, forming a part of thisspecification.

My invention relates to devices for protecting electrical circuits andinstruments from the injurious effects of excessive or unduly strongcurrents.

Prominent objects of the invention are to provide an instrument of thiskind especially adapted for use upon circuits where the current isnormally large, to secure the same degree of accuracy and reliability insuch instruments as is commonly secured in instruments operating uponcircuits where the currents are normally exceedingly small, and tosecure these results in a simple, expeditious, and economic manner.

To the attainment of these and other desired ends my invention consistsin matters hereinafter set forth.

In the accompanying drawings, Figure is a protector embodying myinvention. Figs. 2 and 3 are transverse sections of the same on line a bin Fig. 1, Fig. 2 showing the protector in its normal condition, andFig. 3 showing the same in an operated condition.

In the protector illustrated in the drawings 1 have shown a base A,composed of insulating material-such as slate, porcelain, or the likeprovided with four binding-posts 1 1 and 2 2. The binding-posts 1 1 haveattached to them conductors 3 3, which are understood to be the lineconductors, while the binding-posts 2 2 have attached to them conductorsa 4,which are understood to be the conductors running to the instrumentto be protected. I have shown the two sides, of the circuit arranged inaccordance with my invention. Of course, if desired, but one of suchcircuit-breaking devices could be employed.

In accordance with my invention I provide a low-resistance shunt 5 and ahigh-resistance shunt 6, and I associate with the latter a de viceadapted to open or break the circuit and capable of operating upon arise in the current normally passing through the shunt. In this way itwill be seen that a circuit carrying a heavy current can be opened orbroken by such a sensitive and accurate device as can be operated onlyupon and by low tension and exceedingly small currents. This allows anaccuracy and reliability of operation which cannot be secured bybreaking the circuit by a device capable of carrying the normally largecurrent and operating upon an access in the current.

As a preferred arrangement I employ as the sensitive and low-tensionexcess-operated device a form of current-breaking device illustrated,described, and claimed in my application for United States LettersPatent, Serial No. 618,795, filed January 11, 1897. This device consistsof a couple of metallic rods 7 7, adapted to fit in sockets S 8 in thebase A, a block 9, secured to the upper ends of the rods 7 7, a slide10, arranged to slide upon the lower ends of said rods, springs 11 11,arranged to fit over the rods 7 7 and tending to separate the block 9and slide 10, and a fusible button 12 associated with the block 9 andprovided witha hook 13, which is connected by link 1% with the slide 10.The fusible button 12 contains a coil of line wire, which is included inthe high-resistance shunt 6. By this arrangement the fusible button 12holds the slide 10 normally in such condition that the springs 11 11 areunder tension. \Vhcn, however, an excess current passes through theshunt 6, the button 12 is fused or melted or softened, thereby allowingthe springs 11 to separate the block 9 and slide 10, and so cause thecircuit-breaking device as a whole to rise and break the circuit.

As a convenient arrangen'ient the lowresistance shunt 5 is connectedwith the terminals 15 15, to which the upper ends of the rods 7 7 aresecured. In this way it is obvious that the shunt-circuits are properlyformed, so as to allow only a small portion of the current to passthrough the coil contained in the'fusible button 12, while at the sametime the circuit-breaking device is operated by this small portion ofthe current.

It is understood, of course, that the sockets 8 8 are connected with theterminals 1 1 and 2 2, as by conductors 16 16.

The relative resistances of the shunts 5 and 6 can be so proportioned asto cause any desired portion of the current to pass through thelow-resistance shunts. As a result this simple and desirable form ofcircuit-breaking device, which can be advantageously operated only byvery small currents, can be employed in connection with heavy andpowerful currents.

\Vhat I claim as my invention is- 1. In an electrical protector, thecombination with a pair of terminals, of a plurality of shunts allconnected with said terminals, whereby all of said shunts form a part ofa single circuit, and means controlled by one of said shunts forcontrolling said circuit, substantially as set forth.

2. In a protector for electric circuits, the con'ibination of a coupleof shunts, a circuitbreaking device controlled by one of said shunts,and means for removing both shunts "from the circuit upon the operationof the circuit-breaking device, substantially as set forth.

3. In a protector for electric circuits, the combination with a coupleof shunts, of a circuit-breaking device carrying both of said shunts andcontrolled by one of the same, whereby when the circuit-breaking deviceoperates, both shunts are removed by it from circuit, substantially asdescribed.

at. In a protector for electric circuits, the combination of a circuitbreaking device adapted to operate so as to spring bodily out of itscooperating contacts, and a couple of shunts carried by saidcircuit-breaking device and controlled by one of the same, whereby whenthe device operates, both shunts are removed bodily from circuit,substantially as described.

5. In a protector for electric circuits, the combination of a pair ofseparate metal rods; a block securing the upper ends of the rodstogether; sockets into which the rods can fit; a slide arranged upon theends of the rods, which lit into the sockets; springs arranged toseparate the slide and the block; a fusible or so'ftenable buttonconnected with the slide; a coil of line wire associated with the buttonand connected to the ends of the metallic rods; and a low-resistanceshunt arranged around the coil of fine wire, substantially as described.

6. In a protector for electric circuits, the combination of a circuitbreaking device adapted for bodily movement so as to spring out of itscooperating contacts, high andv low resistance shunts mounted upon saidcircuitbreaking device, and an excess-cturent-operated device includedin the high-resistance shunt and adapted to operate to actuate thecircuit breaking device upon the passage 'therein of an unduly strongcurrent, substantially as described.

7. In an electrical protector, the combination with a pair of terminals,of a plurality of shunts all connected with said terminals, whereby allof said shunts form part of a single circuit, and means controlled byone of said shunts for opening the circuit, substantially as set forth.

8. In an electric-circuit protector, the combination with a pair ofterminals, of a plurality of shunts connected with said terminals,whereby all of said shunts form part of a single circuit, one of saidshunts having a relatively high resistance, and means controlled by saidhigh-resistance shunt for controlling said circuit, substantially asdescribed.

9. In an electric-circuit protector, the combination with a pair ofterminals, of a plurality of shunts connected with said terminals,whereby all of said shunts form part of a single circuit, one of saidshunts having a relatively high resistance, and means controlled by saidhigh-resistance shunt for opening said circuit, substantially asdescribed.

10. In an electriccircuit protector, the combination with a pair ofterminals, of a pair of shunts both connected with said tern'iinals,whereby both of the shunts are connected in parallel with the circuitattached to the ter minals, and a thermal eXcess-current-operated deviceconnected in one of said shunts, whereby such shunt becomes ahigh-resistance shunt relatively to the other one, said device beingadapted to control the circuit upon the pars sagetherein of an undulystrong current, substantiall y as described.

11. The combination with a plurality of shunts, of a circuit-bro; kingdevice adapted to bodily remove said shunts from circuit, and means,subject to one of said shunts, for actuating said circuit-lneakingdevice, substantially as described.

12. In an electric-circuit protector, thecombination with a pair ofterminals, of a pair of shunts both connected with said terminals,whereby both of the shunts are connected in parallel with the circuitattached to the terminals, and a thermal excess-curreilt-operated deviceconnected in one of said shunts, whereby such shunt becomes ahigh-resistance shunt relatively to the other one, said device beingadapted to open the circuit upon the passage therein of an unduly strongcurrent, substantially as described.

In witness whereof .I hereunto subscribe my name this 16th day of April,A. I). 1900.

CHARLES A. RULFIC.

\Vitnesses:

A. I\IILL1GR l-llcnrncto, CHAS. I IIUmnrr.

IIO

